Burner arrangement

ABSTRACT

A burner arrangement includes a carrier and at least two burners which are mounted on the carrier in a flow direction Each burner includes a cylindrical housing having a lance which is arranged centrally therein and having a fuel duct and which is supported on the housing via swirl blades. An attachment is arranged on the side leading to a combustion chamber At least one fuel nozzle is disposed in the attachment and is connected to the fuel duct. The at least two fuel nozzles of the at least two burners have a different functional characteristic and/or spray form, and the at least two fuel nozzles of the at least two burners with a different functional characteristic and/or spray form include at least one full jet nozzle and at least one pressure swirl nozzle.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is the US National Stage of International Application No. PCT/EP2011/064072, filed Aug. 16, 2011 and claims the benefit thereof. The International Application claims the benefits of European application No. 10174338.3 EP filed Aug. 27, 2010. All of the applications are incorporated by reference herein in their entirety.

FIELD OF INVENTION

The present invention relates to a burner arrangement.

BACKGROUND OF INVENTION

When the gas turbine is in operation, compressed air is delivered to the combustion chamber from the compressor. The compressed air is mixed with a fuel, for example oil or gas, and the mixture is burnt in the combustion chamber. The hot combustion exhaust gases are finally delivered as working medium, via a combustion chamber outlet, to the turbine where, being expanded and cooled, they transmit a pulse to the moving blades and thus perform work.

A burner arrangement has a carrier with at least two burners which are mounted on the carrier in the flow direction. Each burner comprises a cylindrical housing with a lance which is arranged centrally therein and has a fuel duct and which is supported on the housing via swirl blades. In this case, an attachment is arranged on the side leading to a combustion chamber, at least one fuel nozzle in the attachment preferably being arranged downstream of the swirl blades and being connected to the fuel duct. In gas turbines, particularly those which are operated with two different fuels, for example, injection of oil as fuel takes place in the region of swirl generators in which the oil is mixed with air. For better mixing of oil and air, the oil is set in swirling motion within the nozzles used for injection. This oil nozzle is also designated as a pressure swirl nozzle.

It is precisely in the case of gas turbines with two different fuels that the oil nozzles cannot be arranged such that the mixing of the fuel with air leads to an optimal result with regard to the pressure pulsations.

SUMMARY OF INVENTION

The object of the present invention is, therefore to specify a burner arrangement which solves the above problem.

The object is achieved by the features of the independent claim(s). The further subclaims contain advantageous refinements of the invention.

According to the invention, in such a burner arrangement, the at least two fuel nozzles of the at least two burners have a different functional characteristic and/or spray form. This gives rise, with regard to the respective burner, to a different penetration behavior of the fuel, injected through the fuel nozzles, for example into the compressor air. The result of this is that the flame zone of the respective burners has a different stabilization point and is therefore also stabilized differently. With regard to the overall combustion system, this causes blurring of the combustion zones. Such blurring is understood in this context to mean effects, such as, for example the broadening of the flame zone, the avoidance of symmetrical structures and the generation of zones having a different temperature. This leads to an improved thermoaccoustic behavior.

BRIEF DESCRIPTION OF THE DRAWINGS

Further advantages, features and properties of the present invention are described in more detail below by means of exemplary embodiments, with reference to the accompanying figures. The features of the exemplary embodiments may in this case be advantageous individually or in combination with one another.

FIG. 1 shows diagrammatically a section through an individual burner of a burner arrangement according to the invention.

FIG. 2 shows fuel distribution of a first burner arrangement according to the invention with eight burners.

FIG. 3 shows fuel distribution of a second burner arrangement according to the invention with eight burners.

FIG. 4 shows fuel distribution of a third burner arrangement according to the invention with eight burners.

DETAILED DESCRIPTION OF INVENTION

FIG. 1 shows an individual burner 2 of such a burner arrangement according to the invention. Swirl blades 4 are arranged around a lance in the housing 12 of the burner 2 according to the invention. The swirl blades 4 are arranged along the circumference of the lance in the housing 12. A compressor air stream 7 is conducted by the swirl blades 4 into that part of the burner 2 which leads to a combustion chamber (not shown). The air is set in swirling motion by the swirl blades 4. Moreover, the lance comprises a fuel duct 3. Furthermore, the burner 2 comprises an attachment 10 on the side leading to the combustion chamber. The attachment 10 may, for example, be welded or screwed to or cast on directly with the lance. The usually several fuel nozzles 1 are arranged in the attachment 10 preferably downstream of the swirl blades 4 and are in this case flow-connected to the fuel duct 3, illustrated here as an oil duct. Preferably eight such burners 2 are arranged (not shown) in a circle on a carrier. In this case, the burners 2 are arranged around a pilot burner (not shown) having a pilot cone. Moreover, the swirl blades 4 may also have additional fuel nozzles which, however, are not illustrated here.

The at least two burners 2 have fuel nozzles 1 according to the invention, each with a different functional characteristic and/or a spray form. This means that the fuel nozzles 1 of one burner 2 differ in their functional characteristic and/or in their spray form from the fuel nozzles 1 of the other burner 2. Alternatively, three or more burners 2 may also have fuel nozzles 1 according to the invention, each with a different functional characteristic and/or spray form. The number of burners 2 and the number of fuel nozzles 1, each with a different functional characteristic and/or spray form, are therefore not fixed.

The functional characteristic of a fuel nozzle 1 is in this case characterized at least by the nozzle size, the jet angle, the liquid distribution and the atomization characteristic. In this case, the nozzle size essentially fixes the fuel mass flow when there is a given pressure difference. The atomization characteristic in this case comprises at least the drop size distribution. Thus, for example, simple pressure atomizers, swirl nozzles or air-protected atomizers may be used. A distinction can also be made in the spray form, thus the fuel nozzles 1 may, for example, form a full jet, hollow conical jet, full conical jet or flat jet. Other spray forms are also possible. The fuel nozzles 1 of the respective burners 2 have a different distribution and penetration behavior of the fuel into the compressor air stream 7 on account of the different functional characteristic and/or spray form. Thus, for example, a markedly greater depth of penetration of the fuel into the air flow 7 may result in a closer distribution of the fuel around the circumference of the attachment 10. The different distribution and penetration behavior leads to a different stabilization of the flame zone of the respective burners 2. This gives rise to blurring of the combustion zones in the overall combustion system. The energy quantity available in each case for feedback at a specific frequency is thus reduced and falls below a critical limit. This leads to an improved thermoaccoustic behavior.

FIG. 2 shows fuel distribution of a first burner arrangement according to the invention with eight burners 2 a, 2 b from the front. However, the invention is not restricted to eight burners 2 a, 2 b and also a different number of burners is possible. Thus, here, the burners 2 a have fuel nozzles 1 (FIG. 1) with a functional characteristic and spray form which bring about an average radial depth of penetration and broad fuel distribution around the attachment 10. The burner 2 a therefore has a broad fuel distribution ring 19 a around the attachment 10. The fuel distribution ring 19 a is at a long radial distance from the attachment 10.

By contrast, the burners 2 b have fuel nozzles 1 (FIG. 1) with a functional characteristic and spray form which bring about a very low radial depth of penetration and close fuel distribution around the attachment 10. The burner 2 b therefore has a narrow fuel distribution ring 19 b around the attachment 10. Moreover, the fuel distribution ring 19 b is at a short radial distance from the attachment 10. FIG. 2 shows in this case a symmetrical arrangement of burners 2 a, 2 b. In this case, the in each case four burners 2 a having the same functional characteristic and spray form are arranged opposite one another. This applies likewise to the burners 2 b. However, other arrangements may also be possible.

FIG. 3 shows fuel distribution of a second burner arrangement according to the invention with eight burners 2 a, 2 b from the front. In this case, the burners 2 a, 2 b are arranged alternately.

FIG. 2 and FIG. 3 show burner arrangements which have in each case two burners 2 a, 2 b with a different functional characteristic and/or spray form in the fuel nozzles 1 (FIG. 1). However, even several burners 2 with a different functional characteristic and/or spray form in the fuel nozzles 1 (FIG. 1) may be present in such a burner arrangement.

FIG. 4 shows fuel distribution of a third burner arrangement according to the invention with eight burners 2 a, 2 b from the front. In this case, six burners 2 a have fuel nozzles 1 (FIG. 1) with the same functional characteristic and spray form, whereas the other two burners 2 b have fuel nozzles 1 (FIG. 1) with a functional characteristic and/or spray form different from this. In this case, however, the functional characteristic and spray form of the fuel nozzles 1 of the burners 2 b are identical to one another. This corresponds to an asymmetric arrangement of burners 2 a, 2 b. In thermoacoustic terms, such an asymmetric arrangement is, in particular, advantageous in order to prevent circumferential modes in the overall burner system. 

1-10. (canceled)
 11. A burner arrangement, comprising: a carrier, at least two burners which are mounted on the carrier in a flow direction, wherein each burner comprises: a cylindrical housing having a lance which is arranged centrally therein and having a fuel duct and which is supported on the housing via swirl blades, wherein an attachment is arranged on the side leading to a combustion chamber, wherein at least one fuel nozzle is disposed in the attachment and is connected to the fuel duct, wherein the at least two fuel nozzles of the at least two burners have a different functional characteristic and/or spray form.
 12. The burner arrangement as claimed in claim 11, wherein for each of the burners, the at least one fuel nozzle is arranged downstream of the swirl blades.
 13. The burner arrangement as claimed in claim 11, wherein the fuel nozzles with a different functional characteristic differ from one another at least in a nozzle size or a jet angle or liquid distribution or an atomization characteristic.
 14. The burner arrangement as claimed in claim 13, wherein, in the case of a different atomization characteristic of the fuel nozzles, at least the drop size distributions differ from one another.
 15. The burner arrangement as claimed in claim 11, wherein the fuel nozzles with a different spray form form a full jet, or a hollow conical jet, or a full conical jet or a flat jet.
 16. The burner arrangement as claimed in claim 11, wherein the fuel nozzles are oil nozzles.
 17. The burner arrangement as claimed in claim 11, wherein an even number of burners which are mounted in the form of a ring on the carrier is provided.
 18. The burner arrangement as claimed in claim 17, wherein eight or ten or twelve burners are provided.
 19. The burner arrangement as claimed in claim 17, wherein at least four burners are provided, all the burners opposite one another having fuel nozzles with the same functional characteristic and spray form.
 20. The burner arrangement as claimed in claim 17, wherein at least four burners are provided, at least two burners opposite one another having fuel nozzles which have a different functional characteristic and/or spray form.
 21. The burner arrangement as claimed in claim 11, wherein an odd number of burners is provided.
 22. The burner arrangement as claimed in claim 11, wherein the at least two fuel nozzles of the at least two burners with a different functional characteristic and/or spray form comprise at least one full jet nozzle and at least one pressure swirl nozzle. 